US3829237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variably positioned guide vanes for aerodynamic choking
Assignee: National Aeronautics and Space Administration
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Filing: 1972-06-27
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Granted: 1974-08-13
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Expires: 1992-06-27
Abstract
Abstract A choking device to cause a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow in a compressor that may be part of an aircraft gas turbine engine. The noise reduction is accomplished by proper shaping and movement of inlet guide vanes, and an actuator is connected to selected guide vanes to effect movement thereof by programmed amounts as required to choke or partially choke within the design range of the axial-flow-air compressor.
Inventors
- 👤 D Chestnutt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:37
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/66; F04D29/661; F04D29/663; F02; F02C; F02C7/00; F02C7/04; F02C7/045; F04D21/00; F04D27/00; F04D27/02; F04D27/0253; F04D29/40; F04D29/52; F04D29/54; F04D29/56; F04D29/563; F05; F05D; F05D2250/00; F05D2250/50; F05D2250/51; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
180 words
In an axial-flow-air compressor having air inlet means and a plurality of similarly configured inlet guide vanes positioned symmetrically therein, the improvement comprising: a radially and symmetrically positioned plurality of tapered inlet guide vanes in the inlet of an axial-flow-air compressor, capable of adding prewhirl to air flowing thereIn, each of the plurality of guide vanes being relatively elongated along its longitudinal cross-sectional dimension and defining a central raised portion in the form of an underchambered hump along said dimension, positioning means operable to position the plurality of guide vanes in parallel cross-sectional alignment with corresponding points on said humps being substantially coplanar to provide an unchoked condition for the air flow, said positioning means being further selectively operable to simultaneously move the selected ones of the plurality of guide vanes out of said alignment wherein selected humps of the plurality of guide vanes are misaligned to constrict the flow of air to provide a choked condition causing a sonic barrier to be formed which reduced the transmission of noise in a direction opposed to the direction of air flow.
Claim 2
Dependent Claim
180 words
In an axial-flow-air compressor having air inlet means and a plurality of similarly configured inlet guide vanes positioned symmetrically therein, the improvement comprising: a radially and symmetrically positioned plurality of tapered inlet guide vanes in the inlet of an axial-flow-air compressor, capable of adding prewhirl to air flowing thereIn, each of the plurality of guide vanes being relatively elongated along its longitudinal cross-sectional dimension and defining a central raised portion in the form of an underchambered hump along said dimension, positioning means operable to position the plurality of guide vanes in parallel cross-sectional alignment with corresponding points on said humps being substantially coplanar to provide an unchoked condition for the air flow, said positioning means being further selectively operable to simultaneously move the selected ones of the plurality of guide vanes out of said alignment wherein selected humps of the plurality of guide vanes are misaligned to constrict the flow of air to provide a choked condition causing a sonic barrier to be formed which reduced the transmission of noise in a direction opposed to the direction of air flow.
Claim 3
Dependent Claim
35 words
The axial-flow-air compressor recited in claim 1 wherein each of the plurality of inlet guide vane cross-sections comprises substantially straight end portions joined together by said raised portion in the form of an underchambered hump.
Claim 4
Dependent Claim
42 words
The axial-flow-air compressor recited in claim 2 wherein each of the plurality of inlet guide vane cross-sections is tapered to increase in thickness from their straight end portions toward the center of the raised portion, the latter being the thickest dimension thereof.
Claim 5
Dependent Claim
26 words
The axial-flow-air compressor recited in claim 3 wherein the longitudinal axes of the inlet guide vane cross-sections straight end portions are located in the same plane.
Claim 6
Dependent Claim
26 words
The axial-flow-air compressor recited in claim 3 wherein the longitudinal axes of the inlet guide vane cross sections straight end portions are located in parallel planes.
Claim 7
Dependent Claim
35 words
The axial-flow-air compressor recited in claim 1 wherein the positioning means move alternate ones of the plurality of inlet guide vanes out of the said parallel cross-section alignment by movement thereof in an axial direction.
Claim 8
Dependent Claim
170 words
In an axial-flow-air compressor having air inlet means and a plurality of similarly configured inlet guide vanes positioned symmetrically therein, the improvement comprising: A radially and symmetrically positioned plurality of tapered inlet guide vanes in the inlet of an axial-flow-air compressor, capable of adding prewhirl to air flowing therein, each of the plurality of guide vanes being relatively elongated along its longitudinal cross-sectional dimension and defining a central curved portion along said dimension, positioning means operable to position the plurality of guide vanes in parallel cross-sectional alignment to provide an unchoked condition for the air flow, said positioning means being further selectively operable to simultaneously move selected guide vanes out of said alignment by pivoting said selected guide vanes about their own longitudinal axes wherein selected curved portions of the plurality of guide vanes are misaligned to constrict the flow of air to provide a choked condition causing a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow.
Claim 9
Dependent Claim
170 words
In an axial-flow-air compressor having air inlet means and a plurality of similarly configured inlet guide vanes positioned symmetrically therein, the improvement comprising: A radially and symmetrically positioned plurality of tapered inlet guide vanes in the inlet of an axial-flow-air compressor, capable of adding prewhirl to air flowing therein, each of the plurality of guide vanes being relatively elongated along its longitudinal cross-sectional dimension and defining a central curved portion along said dimension, positioning means operable to position the plurality of guide vanes in parallel cross-sectional alignment to provide an unchoked condition for the air flow, said positioning means being further selectively operable to simultaneously move selected guide vanes out of said alignment by pivoting said selected guide vanes about their own longitudinal axes wherein selected curved portions of the plurality of guide vanes are misaligned to constrict the flow of air to provide a choked condition causing a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |